Changing MX IP Address?

Jim Reid jim at rfc1035.com
Thu May 10 18:37:09 UTC 2001


>>>>> "Dan" == Dan Star <danstar at engman-taylor.com> writes:

    Dan> We will need to change our MX IP Address due to a change in
    Dan> ISP.  My question is how can we assure that this IP Address
    Dan> change gets propagated throughout the DNS system so that
    Dan> disruption to email is limited.  Any advice is appreciated.

If you're bring up a new mail server, just add another MX record for
the new system when it's up and running. This MX record will have a
lower preference value than the current one, making mail go to the new
server. If you're just renumbering the existing box, reduce the TTL of
the current MX record to something like 5 or 10 minutes. Do this a
couple of days before renumbering. That way the old MX record doesn't
stay in other name server caches for too long, causing some mail
systems to attempt to deliver to the old, stale address. Then change
the target of the MX record when the mail server moves. Mail should
get delivered to the server's new IP address. Name servers that have
cached the old MX record will expire it after 5 or 10 minutes, so
there should be a negligible delay in mail thoughput.


More information about the bind-users mailing list